In remote manipulation activities, the operators observe the scene on which they are working through windows passing through the protection wall alongside the place where the remote manipulators that they are actuating pass through this same wall. Some off-centre places in the cells, or places concealed by an object situated inside, are however inaccessible to this direct vision. The cells have therefore been equipped with vision aids, such as periscopes or cameras. Periscopes often have the drawbacks of being bulky and to offer only limited additional vision to part of the contents of the cell since their location is fixed; this is why cameras are very good complementary tools since they are inexpensive, portable and lightweight items of equipment, and therefore able to be moved to any place, and because they can also be oriented in all directions inside the cells, allowing almost total visual coverage of the volume of the shielded chamber inside which they are situated.
Several techniques using such cameras have been proposed. In one of them, the camera remains at the end of a movable support comprising a foot placed on a surface of the cell, and a flexible rod rising at the middle of the foot, on which the camera is fixed. The foot is placed close to the required scene, and the camera is placed at the correct orientation by deforming the rod. This device is convenient, but has the drawback that the camera must be refocused before each operation, the support being at variable distances from this scene to be observed.
FR 2 883 147 A and US 2008/056808 A describe flexible supports for objects that have great ease of position adjustment, but which can scarcely be envisaged in the field envisaged here, because of their low rigidity and the difficulty in adjusting them with precision other than manually.
The cameras may also be carried by the remote manipulators themselves. Then two remote-manipulator arms are used, the gripper of one of which holds the camera, whereas the gripper of the other carries out the work being observed. This design therefore has the drawback of occupying a second remote-manipulator arm.
Finally, some designs use a camera mounted permanently on a remote-manipulator arm, or an autonomous remote arm, in order to avoid the drawback of the previous design. US 2010/0158656 A and JP 2007-288010 A disclose such devices, where the camera is mounted on the arm by means of a fixed support, or one that is demountably only manually; however, the arm carrying the camera must then be extracted from the cell when the camera has to be replaced, which requires tedious precautions and work in order to be accomplished in accordance with safety rules. And US 2014/055597 A discloses a device where the camera is mounted on such a support by a connection that makes it possible to replace it easily by remote manipulation, which is advantageous and corresponds to one aim of the present invention; however, the support must remain on the arm, so that the drawbacks of the previous devices remain if the support is also to be changed, or adjusted in another way.